This report describes modifications to a U.S. Geological Survey (USGS) three-dimensional solute-transport model (MODFLOW-GWT), which is incorporated into the USGS MODFLOW ground-water model as the Ground-Water Transport (GWT) Process. The modifications were made to create compatibility between the Multi-Node Well (MNW) Package for MODFLOW and the MODFLOW-GWT model. This compatibility improves the capability of MODFLOW-GWT to represent accurately solute transport in simulations that include multi-node wells because long-screen wells or long open boreholes that extend through multiple model layers can provide fast pathways for solutes to move from one location to another in a ground-water flow system. For nonpumping multi-node wells [...]
